1. Field of the Invention
The present invention relates to improved methods and apparatus for concurrently providing thermal neutron capture gamma-ray spectroscopy measurements and thermal neutron decay time measurements.
2. The Prior Art
U.S. Pat. No. 4,055,763, issued Oct. 25, 1977, to Stephen Antkiw and assigned to the assignee of the present application, discloses a combined thermal neutron capture gamma-ray spectroscopy and decay time (tau) tool in which the timing of the neutron bursts and the gating of the gamma-ray detection periods, both for the spectroscopy measurements and the decay time measurements, are automatically controlled as a function of the real-time-measured value of the decay time. Although the Antkiw tool affords significant advantages over earlier spectroscopy and deacy time measurement apparatus and techniques, it is desirable to provide still further improvements in the making of such combined spectroscopy and decay time measurements. In particular, it has been found that the apparatus as described in the Antkiw patent yielded tau measurements which may be considerably improved statistically with the methods and apparatus of the present invention.
Improvements in the measurement precision of tau result in optimal placement of the detection periods for the spectroscopy measurements.